Isotopic Carbon Dioxide Analyzer for Atmospheric Studies

Isotopic analysis is increasingly employed in studies of the cycles of atmospheric green house gases such as carbon dioxide. Isotopic analysis provides insight into sources, sinks, and transport processes of these important gases, providing greater understanding of the effect of green house gases on climate. Various sources have characteristic isotope ratios, and sink processes have characteristic isotope fractionation. While these sources and sinks have large differences in their isotopic signatures, the terrestrial biosphere source is extremely uncertain because of large seasonal and spatial variability. This variability is difficult to quantify, much less to understand for modeling purposes, because traditional mass spectrometric techniques require laborious collection and processing of air samples within glass flasks. This large uncertainty can cause global carbon cycle models to make erroneous conclusions about the distribution of carbon sources and sinks across the land surface. This project will develop a CO2 isotopic monitor, based on cavity ring-down spectroscopy (CRDS), that is capable of measuring the isotopic composition and the concentration of atmospheric CO2 with high speed, precision, and accuracy. The analyzer is expected to achieve a precision of 0.25¿ for the isotopic measurement of CO2 in a 1-second measurement time. Commercial Applications and other Benefits as described by the awardee: In addition to quantifying and understanding the carbon cycle, the analyzer should provide the high speed, high precision, and high accuracy necessary to provide a greater understanding of various natural and anthropogenic processes, including those related to combustion, enzymatic biochemistry, or resistances to gas or liquid fluxes.